1. Field of the Invention
The present disclosure relates to a starter-use electromagnetic switch.
2. Description of Related Art
Japanese Patent Application Laid-open No. 2008-135344 describes a terminal structure of an electromagnetic switch mounted on a starter. This terminal structure includes an excitation terminal having a plate-like shape and insert-molded in a resin cover, and a connection terminal for electrical connection between the excitation terminal and an excitation coil. A terminal guide section having a tubular shape is provided integrally with the resin cover surrounding the excitation terminal drawn outside penetrating through the resin cover. According to the above terminal structure, the electromagnetic switch can be provided with waterproofness by adapting the shape of the terminal guide section to the shape of a connector of external wires connected to the excitation terminal, and using a sealing member such as a gum seal.
Meanwhile, providing a vehicle with an idling stop system is recognized as one means for CO2 emission reduction. The idling stop system operates to automatically stop an engine of the vehicle by cutting fuel supply to the engine when the vehicle is stopped at an intersection for a red light, or stopped due to traffic jam, for example. However, since the engine idling stop system frequently stops and restarts the engine, usage frequency of the starter is considerably higher for vehicles provided with the idling stop system compared to vehicles not provided with the idling stop system. When an engine is cranked by a starter, a battery voltage momentarily drops considerably because a large current called a rush current flows into a motor of the starter. Accordingly, it may occur that a phenomenon called “instantaneous interruption” in which electric or electronic devices such as a meter, an audio device, and a car navigation system stop operation momentarily when an engine is started by a starter. Hence, a driver or a user of a vehicle provided with the idling stop system may feel uncomfortable each time the engine of the vehicle is restarted by the idling stop system.
Japanese Patent Application Laid-open No. 2010-225596 filed by the applicant of the present invention describes a starter including an auxiliary electromagnetic switch which operates to suppress an inrush current flowing into a motor of a starter in order to prevent the above instantaneous interruption. This auxiliary electromagnetic switch incorporates a resistor interposed in a power supply line for supplying power from a battery to the motor, and is configured to switch between a first current path for passing a current to the motor through the resistor and a second current path for passing a current to the motor bypassing the resistor in interlock with on/off of an electromagnet of the auxiliary electromagnetic switch. Incidentally, although an auxiliary electromagnetic switch included in the starter described in the former patent document (Japanese Patent Application Laid-open No. 2008-135344) is fixed to a starter housing through a bracket, the auxiliary electromagnetic switch does not necessarily have to be mounted on the starter, and it may be disposed near the starter.
However, it is necessary for a vehicle to supply power to the excitation terminal of each of the electromagnetic switch and the auxiliary electromagnetic switch regardless of whether the auxiliary electromagnetic switch is mounted on the starter, or disposed near the starter. Accordingly, since it is necessary to connect cables to the electromagnetic switch and the auxiliary electromagnetic switch separately after the starter is mounted on the vehicle, cable connection work may become difficult due to limited space. If it is possible to connect a cable between the excitation terminal of the electromagnetic switch and the excitation terminal of the auxiliary electromagnetic switch before the starter is mounted on the vehicle, cable connection work is as easy as the case where the starter does not include the auxiliary electromagnetic switch.
However, as described in the former patent document, since only one of the excitation terminal pieces projects from the resin cover, it is impossible to connect a cable between the excitation terminal of the electromagnetic switch and the excitation terminal of the auxiliary electromagnetic switch in advance. To enable cable connection between the excitation terminal of the electromagnetic switch and the excitation terminal of the auxiliary electromagnetic switch, it is necessary to provide an additional metal fitting and provide the terminal structure with waterproofness.